According to the American Kennel Club Canine Health Foundation, dogs heavier than 90 pounds account for approximately one-third of canine diagnoses of bone cancer, or osteosarcoma. While the Labrador retriever isn't the breed most commonly affected, this dreaded and often hereditary disease still claims a lot of Lab victims.
Most bone cancer occurs in the legs' long bones, especially the knee and hock on the rear limbs. In the front limbs, osteosarcoma most often appears on the shoulder or on the carpus, the latter equivalent to a human's wrist. Bone cancer usually spreads rapidly, so the prognosis is not good.
Slightly less than 1 percent of Labs will come down with bone cancer. According to the University of Florida, the exact percentage is 0.94. That's similar to the percentage of golden retrievers, at 1.11 percent, but far below the most frequently affected breed, the Irish wolfhound. That giant breed's incidence of bone cancer is 4.88 percent, followed by the Rottweiler at 4.80 percent. The average mixed-breed dog has a 0.44 percent chance of coming down with the disease.
Other Risk Factors
Middle-age Labs, those roughly 7 to 10 years of age, are more likely to develop bone cancer than younger dogs. Male Labs have a slightly higher incidence of the disease than females, but the opposite is true in breeds such as Great Danes and Rottweilers. Males neutered after the age of 1 year have a lower incidence of bone cancer than those fixed before their first birthday.
This deadly disease first appears as a slight lameness that gets progressively worse. You might also notice swelling on a leg or affected area as a tumor develops, along with extreme fatigue. Because cancer weakens the bone, your Lab might suffer a breakage after a minor mishap or bad step. As the cancer spreads, your dog exhibits obvious signs of pain. Your vet diagnoses osteosarcoma via X-ray and bone biopsy.
Sadly, most cases of bone cancer are incurable. If the cancer has not spread, amputating the leg might prove curative, and it will limit the intense pain even if the disease has metastasized. Treatment options, besides surgery, include chemotherapy and radiation. According to the AKC, 50 percent of dogs treated for osteosarcoma live one year or longer after going through current treatment protocols. Your vet will also prescribe medication for pain management, so your Lab can enjoy a reasonable quality of life.
- Rhodesian Ridgeback Club of the United States: Osteosarcoma - The Nemesis of Large Breed Dogs
- University of Pennsylvania School of Veterinary Medicine: Malignant Bone Tumors in the Dog
- Mar Vista Animal Medical Center: Canine Osteosarcoma
- petMD: Bone Cancer (Osteosarcoma) in Dogs
- American Kennel Club Canine Health Foundation: Bone Cancer in Dogs
Jane Meggitt has been a writer for more than 20 years. In addition to reporting for a major newspaper chain, she has been published in "Horse News," "Suburban Classic," "Hoof Beats," "Equine Journal" and other publications. She has a Bachelor of Arts in English from New York University and an Associate of Arts from the American Academy of Dramatics Arts, New York City.